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Finding the Fourth Proportional to 486.28, 669.18 and 420.40

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Solution

The fourth proportional to 486.28, 669.18 and 420.40 is: 578.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    486.28 : 669.18 = 420.40 : x
  2. Step 2: Convert to fraction form
    486.28/669.18 = 420.40/x
  3. Step 3: Cross multiply
    486.28x = 669.18 × 420.40
  4. Step 4: Simplify right side
    486.28x = 281,323.27
  5. Step 5: Solve for x
    x = 281,323.27/486.28
  6. Step 6: Final answer
    x = 578.52

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.